The present invention relates generally to an apparatus for the lateral straightening or alignment of sheet material located on a conveyor and more particularly to an apparatus for aligning folded printed paper booklets commonly known as signatures, i.e. overlapping, stream from a preceding web press, combination folder or flow folding station.
The printing industry yields a vast amount of sheet-like product or articles which have a major plane and a typically rectangular or square perimeter. These articles, or xe2x80x9csignaturesxe2x80x9d as they are referred to in the art, leave the printing press or folding machine where they are subsequently acted upon in a stream in some way. For example, they may be counted, folded, cut, etc. perhaps on their way to be eventually stacked. These successive articles have a forward end and a back end where the front of the articles overlap the back of the succeeding articles to form a shingled stream. As such, the stream is transferred from one operation to the next, such as to further delivery equipment, and eventually leading to a stacking machine where a preset number of articles may form a stack and become ready for further processing or transportation.
The stream of articles from the printing press or folding station are usually, for one reason or another, considerably out of alignment. Accordingly, it is necessary to employ a means to align the signatures before they are fed to the next operation. To achieve accurate alignment it has been customary in the past to employ vibrating joggers acting upon the presented edges of the signatures on either one or both sides of the stream. Such joggers have worked satisfactorily where the amount of misalignment of a given signature with respect to the stream is small, where the signatures are made of relatively stiff paper stock, and where the friction between adjacent signatures is not excessive. However, under more severe conditions, these conventional joggers have proved rather inadequate. For example, under gross misalignment and/or the use of flimsy stock having a high coefficient of friction, the engaged edge, or corner, of the signature is simply bent over rather than being pushed into the desired aligned position, thereby compounding the misalignment and making subsequent downline processing impossible.
Typically, such joggers include a fixed slide plate on one side of the signature stream and a pivoted jogger plate on the other side which is pivoted back and forth so that it alternately slightly compresses the signature flow against the fixed slide plate and then releases the signature flow to provide a rough alignment of the overlapped signatures. Alternatively, such joggers may include dual pivoted adjacent jogger plates. In any event, these joggers are necessarily cam actuated, and, notwithstanding the previously discussed problems, such cam actuation presents a machine movement problem. In particular, since the articles are alternately bent and then are allowed to straighten suddenly as the cam operates, the sudden straightening frequently causes the signatures to again bounce out of alignment. This problem is intensified at high speeds since the oscillation action has a tendency to disturb the alignment with respect to articles in both the downstream and upstream line.
Another typical jogger design includes guide members in the form of endless belts arranged on opposite sides of the stream. These belts are moving in the same direction and at approximately the same speed as the stream as they are continuously conveying/diverging towards/away from one another at the width of the stream. Thus, the sides of the belts running along the stream reciprocally move towards one another to the width of the stream to move together the disordered articles. Although this design may facilitate some of the previously-mentioned problems, it does not solve all of them, and, in fact, amplifies the signature bending drawback. In particular, when a signature is not in alignment, one of its corners is necessarily forced in towards the stream for realignment. However, since one corner is out of alignment, the opposite corner must be out of alignment as well and is similarly forced in towards the stream for realignment. Thus, the signature is susceptible to bending, thereby causing the shingled stream to progress increasingly out of alignment, thereby reversing the joggers"" purpose.
Irrespective of which current jogger design is utilized, the deficiencies yet remain. These deficiencies lead to down-time and loss of operating efficiency in the conveyor system. This subsequently is responsible for the delay and/or cancellation in the product delivery system. Therefore, article jogging, which leads to correct stream alignment is essential to maintain a low cost and expense of the system while ensuring a timely delivery of the product.
By contrast to the current jogger designs, the present invention laterally straightens the alignment of sheet material located on a conveyor without the disadvantages of the aforementioned deficiencies. Accordingly, it is an object of the present invention to provide a new and improved article jogging apparatus that overcomes the deficiencies of the current practices whereby an apparatus is provided for the alignment of signatures which minimizes cost while ensuring a timely delivery.
It is an object of the present invention to provide an article jogging apparatus that reduces the occurrence of bending articles due to inadequate camming actuation.
It is another object of the present invention to provide an article jogging apparatus that reduces the occurrence of bending articles due to adjacent reciprocating jogger belts.
Yet another object of the present invention is to provide an article jogging apparatus that disturbs only the misaligned articles, bringing them back into alignment, without disturbing the properly-aligned articles.
It is yet another object of the present invention to provide an article jogging apparatus capable of accommodating various product widths.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.
According to the present invention, there is provided an apparatus for aligning sheet like articles in a stream carried on a conveyor surface moving at a predetermined speed. The stream is passed between two guide members having vertically arranged timing belts moving at the same speed as the stream. One guide member is fixedly positioned relative to one edge of the stream, while the other is positioned adjacent thereto and oscillating between a reference position and a thrown position. The thrown position thereof urging misaligned articles back into stream alignment.